I sat on a jury in a case that involved allegations of rape. One constant refrain from the nurses who examine rape victims is that there is often little to no physical trauma even when there has been a struggle. Furthermore, except in cases where it's a totally random event, the victim ofte may know the person. Even in the case where someone meets a person in a club and goes home with them, there are still legitimate explanations for lots of the physical evidence. So then it all comes down to whether or not you believe the plantiff or not. Shows like CSI and NCIS make people think that all kinds of science can prove this stuff, but in reality, the evidence is never as clear cut as you would like to think.